ext/khetai/khetai.c in khetai-0.2.0 vs ext/khetai/khetai.c in khetai-0.2.1

@@ -1,17 +1,69 @@
 #include <ruby.h>
 #include <stdlib.h>
 #include <time.h>
 #include "khetai_lib.h"
 
-VALUE move(VALUE self, VALUE board_array, VALUE player, VALUE max_depth, VALUE _max_time)
+VALUE move(VALUE self, VALUE board_array, VALUE _player, VALUE _max_depth, VALUE _max_time)
 {
+    // verify parameters
+    int player = NUM2INT(_player);
+    if (player < 0 || player > 1)
+    {
+        rb_raise(rb_eArgError, "player must be 0 (silver) or 1 (red)");
+    }
+
+    int max_time = NUM2INT(_max_time);
+    if (max_time < 1)
+    {
+        rb_raise(rb_eArgError, "max_time (seconds) must be 1 or greater");
+    }
+
+    int max_depth = NUM2INT(_max_depth);
+    if (max_depth < 2 || max_depth > 25)
+    {
+        rb_raise(rb_eArgError, "max_depth (ply) must be between 2 and 25");
+    }
+
     srand((unsigned)time(NULL));
 
+    unsigned int array_size = (unsigned int)RARRAY_LEN(board_array);
+
+    // verify board_array is valid
+    if (array_size != 80)
+    {
+        rb_raise(rb_eArgError, "board_array must have exactly 80 elements");
+    }
+    const char valid_pieces[] = {'L', 'A', 'X', 'P', 'S', 'p', 'a', 'x', 's', 'l'};
+    size_t valid_pieces_count = 10;
+    for (unsigned int i = 0; i < array_size; i++)
+    {
+        VALUE element = rb_ary_entry(board_array, i);
+        if (!RB_TYPE_P(element, T_STRING) || RSTRING_LEN(element) != 2)
+        {
+            rb_raise(rb_eArgError, "each element in the board_array must be 2 characters");
+        }
+
+        // check if element in board_array is a valid string
+        const char *element_str = RSTRING_PTR(element);
+        int is_valid = 0;
+        for (unsigned int j = 0; j < valid_pieces_count; j++)
+        {
+            if ((element_str[0] == valid_pieces[j] && element_str[1] >= '0' && element_str[1] <= '3') || strcmp(element_str, "--") == 0)
+            {
+                is_valid = 1;
+                break;
+            }
+        }
+        if (!is_valid)
+        {
+            rb_raise(rb_eArgError, "each element in the board_array must be a valid piece (example: 'p1') or empty ('--')");
+        }
+    }
+
     // khetai_lib assumes an extra level of padding around the board
     char *init_board[120];
-    unsigned int array_size = (unsigned int)RARRAY_LEN(board_array);
 
     // top and bottom row padding
     for (unsigned int i = 0; i < 12; i++)
     {
         init_board[i] = "--";
@@ -23,11 +75,11 @@
     {
         init_board[12 * (i + 1)] = "--";
         init_board[12 * (i + 2) - 1] = "--";
     }
 
-    // fill in the rest of the baord passed from ruby
+    // fill in the rest of the board passed from ruby
     for (unsigned int i = 0; i < array_size; i++)
     {
         VALUE square = rb_ary_entry(board_array, i);
         init_board[13 + ((i % 10) + ((i / 10) * 12))] = StringValueCStr(square);
     }
@@ -35,20 +87,19 @@
     reset_undo();
     init_zobrist();
     setup_board(init_board);
 
     time_t start_time = time(NULL);
-    int max_time = NUM2INT(_max_time);
     set_time_parameters(max_time, start_time);
 
     // iterative deepening
     int depth = 1;
     Move best_move = (Move)0;
     Move current_move = (Move)0;
-    while ((time(NULL) - start_time < max_time) && (depth <= NUM2INT(max_depth)))
+    while ((time(NULL) - start_time < max_time) && (depth <= max_depth))
     {
         best_move = current_move;
-        current_move = alphabeta_root(depth, NUM2INT(player));
+        current_move = alphabeta_root(depth, player);
         depth++;
     }
     make_move(best_move);
 
     VALUE out = rb_ary_new2(3);